The results show that the main parameter that influences the visualization of B-lines is the frequency rather than the focal point or the number of transmitting elements.The system formed by a trumpet player and his/her instrument can be seen as a non-linear dynamic system and modeled by physical equations. Numerical tools can then be used to study these models and clarify the influence of the model parameters. The acoustic input impedance, for instance, is strongly dependent on the geometry of the air column and is therefore of primary interest for a musical instrument maker. In this study, a method of continuation of periodic solutions based on the combination of the Harmonic Balance Method (HBM) and the Asymptotic Numerical Method (ANM) is applied to a physical model of brass instruments. It allows the study of the evolution of the system where one parameter of the model (static mouth pressure) varies. This method is used to compare different B♭ trumpets on the basis of two descriptors (hysteresis behavior and dynamic range) computed from the continuation outputs. Results show that this methodology enables the differentiation of instruments in the space of the calculated descriptors. Calculations for different values of the lip parameters are also performed to confirm that the obtained categorization is independent of variations of lip parameters.High intensity focused ultrasound (FUS) is a noninvasive technique for treatment of tissues that can lie deep within the body. There is a need for methods to rapidly and quantitatively map FUS pressure beams for quality assurance and accelerate development of FUS systems and techniques. However, conventional ultrasound pressure beam mapping instruments, including hydrophones and optical techniques, are slow, not portable, and expensive, and most cannot map beams at actual therapeutic pressure levels. Here, a rapid projection imaging method to quantitatively map FUS pressure beams based on continuous-wave background-oriented schlieren (CW-BOS) imaging is reported. https://www.selleckchem.com/products/GSK690693.html The method requires only a water tank, a background pattern, and a camera and uses a multi-layer deep neural network to reconstruct two-dimensional root-mean-square (RMS) projected pressure maps that resolve the ultrasound propagation dimension and one lateral dimension. In this work, the method was applied to collect beam maps over a 3?×?1?cm2 field-of-view with 0.425?mm resolution for focal pressures up to 9?MPa. Results at two frequencies and comparisons to hydrophone measurements show that CW-BOS imaging produces high-resolution quantitative RMS projected FUS pressure maps in under 10?s, the technique is linear and robust to beam rotations and translations, and it can map aberrated beams.This paper presents a method to calculate the bistatic response of an elastic object immersed in a fluid using its structural Green's function (in vacuo structural admittance matrix), calculated by placing the object in a spatially random noise field in air. The field separation technique and equivalent source method are used to reconstruct pressure and velocity fields at the object's surface from pressure measurements recorded on two conformal holographic surfaces surrounding the object. Accurate reconstruction of the surface velocity requires subtraction of the rigid body response computed using a finite element approach. The velocity and pressure fields on the surface lead to the extraction of the in vacuo structural admittance matrix of the elastic object, which is manipulated to yield the farfield bistatic response for a fluid-loaded target for several angles of incidence. This method allows the computation of the scattering properties of an elastic object using exclusive information calculated on its surface (no knowledge of the internal structure required). A numerical experiment involving a cylindrical shell with hemispherical caps is presented, and its bistatic response in water shows excellent agreement with a finite element solution.Recent estimates based on shipboard echosounders suggest that 50% or more of global fish biomass may reside in the mesopelagic zone (depths of ?200-1000?m). Nonetheless, little is known about the acoustic target strengths (TS) of mesopelagic animals because ship-based measurements cannot resolve individual targets. As a result, biomass estimates of mesopelagic organisms are poorly constrained. Using an instrumented tow-body, broadband (18-90?kHz) TS measurements were obtained at depths from 70 to 850?m. A comparison between TS measurements at-depth and values used in a recent global estimate of mesopelagic biomass suggests lower target densities at most depths.The European Region of the World Health Organization (WHO) recently published revised recommendations for transportation noise exposure intended to limit adverse health effects. WHO's newly recommended "safe" limit for aircraft noise exposure is about an order of magnitude lower than the limits currently adopted by most European countries. WHO defines "safe exposure" as the level corresponding to an annoyance prevalence rate of 10% highly annoyed. The revised recommendations are based on a limited selection of post-2000 publications. About half of the cited studies rely on nonstandard questionnaires, respondent selection, and definitions of annoyance prevalence rates which over-estimate annoyance. A re-analysis of a larger and more representative selection of studies that relies on standard procedures shows that no meaningful changes in prevalence rates of high annoyance with aircraft noise have occurred and that existing evidence does not support WHO's revised recommendations.An additional length model is usually used to describe the reactive part of the impedance end correction of microperforated panels, which is extended to describe the resistive part. The cross-sectional impedance is computed along the axis of one perforation cell with a circular hole. Except for the obvious jumps in the narrow regions at the inlet and outlet of the perforation, the impedance varies linearly along the axis following exactly that of the viscous wave in the circular hole. The additional length for the impedance end correction is obtained by extrapolating the linearly varying impedance inside the hole. Empirical models for the resistive and reactive additional lengths are obtained based on the thermoviscous acoustic simulation with 96 test cases. Within an error of about 10%, a unified additional length model is presented for both the resistive and reactive parts of the impedance end correction. Comparison with other existing models shows the accuracy of the proposed model.